Sewing machine throat plate fastening means



Oct. 30, 1962 R. E. JOHNSON SEWING MACHINE THROAT PLATE FASTENING MEANS Filed Jan. 25, 1960 Fig. 3.

IN V EN TOR. RALPH E. Jomvsozv BY M f jammy 2s WITNESS W i r 44 United States Patent 3,060,878 SEWING MACHWE THRUAT PLATE FASTENING MEANS Ralph E. Johnson, Mountainside, N.J., assignor to The Singer Manufacturing Company, Elizabeth, N.J., a corporation of New Jersey Filed Jan. 25, 196i], Ser. No. 4,280 4 Claims. (Cl. 112-260) The present invention relates to sewing machines and particularly to fastening means for securing a throat plate in a sewing machine.

The object of this invention is to provide a throat plate fastening means which will provide for convenient removal and replacing of the throat plate and which is simple and economical and will effectively hold the throat plate in position.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:

FIG. 1 is a fragmentary top plan view of the bed of a sewing machine embodying the present invention, and with the throat plate and slide plate removed,

"FIG. 2 is a fragmentary bottom view of the bed of the sewing machine of FIG. 1,

FIG. 3 is a sectional view taken substantially on the line 33 of FIG. 1, but with the throat plate added and in section,

FIG. 4 is a plan view of the throat plate per se.

The present invention is herein illustrated as embodied in the sewing machine forming the subject matter of the United States patent. application of Johnson, Serial No. 4,430, filed January 25, 1960, wherein the machine is fully disclosed and to which reference may be had for a complete understanding of the machine.

With reference to the drawings, there is illustrated the bed 1 of the frame of a sewing machine. The top of the bed 1 is formed by a bed plate 2, the upper surface 3 of which constitutes the work supporting surface of the machine. Depending from the periphery of the bed plate 2 is a front wall 4, a rear wall 5 and an end wall 6.

The bed plate 2 is provided with an opening 7 beneath which is mounted a loop taker which is a vertical axis oscillating hook 8 mounted upon a hook shaft 9 journaled in a wall 10 integral with the bed plate 2. Surrounding the opening 7 there is provided a seat 11 in the bed plate 2 which receives a throat plate 12 and a slide plate (not shown) for normally closing the opening 7. The throat plate 12 is formed with a needle aperture 14 and feed dog slots 15, the direction of which slots 15 indicate the line of feed of the machine.

For releasably securing the throat plate 12 on the seat 11, there is provided a pin 16 and a plunger 17 arranged on opposite sides of the throat plate 12 transversely of the line of feed. The pin 16 is press or taper fitted into a wall 18 integral with the bed plate 2 and having an upper surface forming a part of the seat 11 so that the head of the pin 16 in effect is upstanding from the seat 11. The throat plate 12 is provided with an aperture 19 that slidingly receives the head of the pin 16. The height of the pin 16 above the seat 11 is made equal to the thickness of the throat plate 12 so that the upper end of the pin is flush with the top of the throat plate.

The plunger 17 extends through and is mounted for endwise sliding in a bore 20 in a wall 21 integral with "ice the bed plate 2 and having an upper surface forming a part of the seat 11. The plunger 17 has a head 22 at its upper end that overlies the seat 11. The plunger has a compression spring 23 coiled about it beneath the wall 21 and the spring at its upper end bears against the underside of the Wall 21. The spring 23 has the lower end 24 thereof formed to enter a groove 25 in the plunger 17, thus anchoring the lower end of the spring to the plunger and, in effect, defining an abutment for the lower end of the spring.

The throat plate 12 has a slot 26' extending inwardly from the edge thereof and terminating in a seat 27 that receives the head 22 of the plunger 17. The seat 27 has a bottom surface opposed to the underside of the head 22, which surface is planar and is inclined relatively to the plane normal to the axis of the plunger 17, with a maximum depth from the top of the throat plate 12 adjacent to the edge thereof and a minimum depth at a point 28 inwardly of the throat plate 12 substantially on a line transversely of the line of feed. The underside of the head 22 is planar and is normal to the axis of the plunger 17 so that the opposed surfaces of the head 22 and the seat 27 will engage only at the minimum depth point 28. Thus, the action of the spring 23 is applied more closely to the center of the throat plate 12, and acts to pivot the same about the point of engagement of the throat plate 12 at the open end of the slot 26 on the seat 11.

The throat plate is easily removed by lifting the side thereof off the pin 16 and sliding it from beneath the head 22 of the plunger 17. It is replaced equally as easily by inserting it under the head 22 With the plunger 17 passing into the slot 26 until the head 22 snaps into the seat 27.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine having a frame, including a bed having a bed plate, said bed plate having an opening and a throat plate seat about said opening, a throat plate mounted on said seat and closing said opening, and means for releasably securing said throat plate on said seat comprising a stationary pin secured in said bed and projecting from said seat, a plunger mounted for endwise movement in said bed and projecting from said seat, a head on the end of said plunger and overlying said seat, spring means for biasing said plunger to move said head toward said seat, said throat plate having an aperture for receiving said pin and providing for movement of said throat plate axially of said pin but constraining said throat plate against movement laterally of said pin, said throat plate having a slot extending inwardly from the edge thereof for receiving said plunger and terminating in a seat for receiving the head of said plunger, said plunger and the seat in said throat plate having opposed surfaces relatively formed to engage at a point disposed inwardly of said throat plate with respect to said plunger.

2. In a sewing machine in accordance with claim 1 in which said bed includes a wall through which said plunger extends, said plunger has an abutment on the end thereof opposite from said head, and said spring means comprises a compression spring surrounding said plunger between and acting against said abutment and said wall.

3. In a sewing machine having a frame including a bed having a bed plate, said bed plate having an opening and a throat plate seat about said opening, a throat plate mounted on said seat and closing said opening, and means for releasably securing said throat plate on said seat comprising a stationary pin secured in said bed and projecting from said seat, a plunger mounted for endwise movement in said bed and projecting from said seat, a head on the end of said plunger and overlying said seat, spring means for biasing said plunger to move said head toward said seat, said throat plate having an aperture for receiving said pin and providing for movement of said throat plate axially of said pin but constraining 'said throat plate against movement laterally of said pin,

mounted in the seat in said throat plate for engagement of said opposed surfaces at a point disposed inwardly of said throat plate relatively to said plunger.

4. In a sewing machine in accordance with claim 3 in which said opposed surfaces include a surface on said head that is normal to the axis of said plunger and a surface on the seat in said throat plate that is inclined relatively thereto.

References Cited in the file of this patent UNITED STATES PATENTS Switzerland Feb. 1, 1951 

